1. Field:
The invention disclosed and claimed herein is in the field of semiconductor devices and processes for their manufacture. Specifically the invention is directed toward the preparation of light emitting diodes (LEDs) and toward the structure of such diodes.
2. Prior Art:
The capability of certain semiconductor materials such as gallium phosphide (GaP), gallium arsenide (GaAs), and gallium arsenide phosphide (GaAsP), when in p-n junction configuration, to emit visible light in certain regions of the spectrum at extremely low power dissipation levels would seemingly make these materials prime candidates for use in the production of solid state displays. However, pure electroluminescent materials of this type are expensive, being difficult and costly to produce in large single crystals which heretofore have been required for display devices, and therefore solid state displays consisting of these materials have found only limited use, existing principally as laboratory curiosities. Typically GaP and GaAs single crystals are grown in relatively small diameter form by the Bridgeman or Czochralski method, the crystals are therefore sawed into wafers, and the same material of which the crystal is composed is ultimately epitaxially deposited in appropriately doped form and desired pattern on the wafer to provide a monolithic array of light emitting diodes.
Manifestly, it would be desirable to provide monolithic displays capable of functioning in an identical manner to those described above, but without need for the costly basic materials heretofore employed. It is the principal objective of the present invention to provide low cost monolithic semiconductor light emitting displays and processes for making such displays.